1. Field of the Invention
This invention relates to electric autoinflators for inflating inflatable articles such as personal floatation devices, rafts, buoys and emergency signalling equipment. More particularly, this invention relates to electric autoinflators which are actuated upon being immersed in water for a predetermined delay period.
2. Description of the Background Art
Presently there exists many types of inflators designed to inflate inflatable articles such as personal floatation devices (life vests, rings and horseshoes), life rafts, buoys and emergency signalling equipment. These inflators typically comprise a body for receiving the neck of a cartridge of a compressed gas such as carbon dioxide. A reciprocating firing pin is disposed within the body for piercing the frangible seal of the cartridge to permit the compressed gas therein to flow into a manifold in the body and then into the device to be inflated. Typically, a manually-movable firing lever is operatively connected to the firing pin such that the firing pin pierces the frangible seal of the cartridge upon manual movement of the same. U.S. Pat. No. 3,809,288, the disclosure of which is hereby incorporated by reference herein, illustrates one particular embodiment of the manual inflator.
While these manual inflators work suitably well, it was quickly learned that in an emergency situation, the person needing the assistance of the inflatable device, such as a downed aviator, injured person, child, or a man overboard, would fail or be unable to manually actuate the inflator. In other applications, such as sonobuoys, automatic actuation is imperative. Accordingly, it was realized that a means must be provided for automatically actuating the inflator in such situations and applications.
In response to this need, water-activated automatic inflators have been developed which, when exposed to a fluid such as water, automatically actuate the firing pin of the inflator causing inflation of the inflatable device.
One type of water-activated automatic inflator comprises a water-activated trigger assembly including a water destructible or dissolvable element which retains a spring-loaded actuator pin in a cocked position in alignment with the firing pin. Upon immersion in water causing the element to destruct or dissolve, the spring-loaded actuator pin is released to forcibly move from the cocked position to an actuated position to strike the firing pin, either directly or indirectly by means of an intermediate transfer pin. Upon striking the firing pin, the pin fractures the seal of the cartridge thereby allowing the gas contained therein to flow into the inflatable device to inflate the same. U.S. Pat. Nos. 3,997,079; 4,223,805; 4,267,944; 4,260,075; and 4,627,823, the disclosures of each of which are hereby incorporated by reference herein, illustrate several examples of water-activated automatic inflators which employ a dissolvable element.
While the above automatic inflators work quite well to automatically inflate the inflatable device in the event of an emergency situation or other application, one major disadvantage to these automatic inflators is their tendency to self-actuate while stored for subsequent exigent use. Specifically, it is not uncommon for the automatic inflator to be stored in a highly humid environment such as on a ship or on a boat. Over a period of time, the moisture contained within the humid air is absorbed by the water dissolvable element to such a degree that the element is weakened, particularly since the element is continually subjected to the force of the actuator spring. As the element gradually weakens, the strength of the element eventually becomes insufficient to retain the spring-loaded actuator pin in the cocked position. The element then collapses under the force of the compressed spring of the actuator pin and the actuator pin strikes the firing pin thereby causing premature and unintentional inflation of the inflatable device.
The problem of premature and unintentional actuation of the automatic inflator is so acute that it is not uncommon for a weakened water destructible or dissolvable element to be replaced with a new element on a periodic basis pursuant to a regularly scheduled maintenance plan. In this regard, it is noted that each of the prior art water-activated automatic inflators disclosed in the above referenced patents teach a structure which may be easily disassembled to facilitate removal of a weakened element and the installation of a new one. Indeed, U.S. Pat. No. 4,627,823 discloses a safety-latched automatic actuator designed to release the pressure exerted on the water-dissolvable element until such time as an emergency situation exists.
Another type of a water-activated automatic inflator comprises a water-activated, squib-powered inflator. As the term is commonly used, a squib is a self-contained explosive charge. Upon actuation by electric current, the explosive charge explodes to actuate the inflator. U.S. Pat. Nos. 3,059,814; 3,091,782; 3,426,942; 3,579,964; 3,702,014; 3,757,371; 3,910,457; 4,382,231; 4,436,159; 4,513,248; 5,026,310; and 5,076,468, the disclosures of each are hereby incorporated by reference herein, illustrate several examples of water-activated squib-powered inflators.
A still other type of water-activated automatic inflator comprises a fusible link assembly which retains a spring-loaded actuator pin in a cocked position in alignment with the firing pin, either directly or indirectly by means of an intermediate transfer pin. Upon exposure to water, electrical current is supplied to a heater wire, wrapped around the fusible link. Upon melting of the fusible link, the actuator pin strikes the firing pin to fracture the seal of the cartridge thereby allowing the gas contained therein to flow into the inflatable device to inflate the same. See generally, U.S. Pat. No. 3,008,479.
It is noted that in both the squib-powered and the fusible link inflators noted above, water-sensing circuitry is provided for sensing the presence of water. In this regard, prior art circuitry is illustrated in U.S. Pat. No. 5,026,310 noted above, and in U.S. Pat. No. 4,714,914, the disclosure of which is incorporated by reference herein. More particularly, the circuitry disclosed in the last mentioned patent above, includes a delay feature which causes actuation only upon being immersed in water (or other liquid) for a predetermined period of time, such as for five seconds. In this manner, unintended actuation is prevented in the event that the sensing circuitry is merely splashed with water.
There exists a continuing need for improved inflators that operate more reliably when immersed in water and which, after firing causing inflation of the inflatable device, may be easily disassembled so as to install a new firing mechanism and a new gas cartridge.
Therefore, it is an object of this invention to provide an apparatus which overcomes the aforementioned inadequacies of the prior art autoinflators and provides an improvement which is a significant contribution to the advancement of the autoinflator art.
Another object of this invention is to provide a fusible link actuator assembly positioned within the longitudinal bore of an autoinflator body and including an actuator housing including a blind link hole defining an opened rearward end, an actuator cap positioned over the opened end, and a pair of retaining balls protruding from opposing sides of the actuator housing which engage into corresponding slots in the longitudinal bore to retain the actuator housing in a cocked position, a slidable link positioned within the blind link hole, the slidable link including an annular groove positioned about its circumference at a rearward portion thereof and a blind spring hole opening rearwardly, a compression link spring positioned within the blind spring hole for urging the slidable link forwardly, a fusible link interconnecting the actuator cap and the slidable link for retaining the slidable link rearwardly in a cocked position within the blind link hole, and means for fusing the fusible link upon being supplied electrical current thereto.
Another object of this invention is to provide an ejector lever operatively positioned within the longitudinal bore of an autoinflator having an actuator assembly for ejecting the actuator assembly after firing.
Another object of this invention is to provide a window means positioned in an autoinflator relative to the longitudinal bore to visually indicate when the actuator assembly has been actuated.
Another object of this invention is to provide an autoinflator body including an open-ended battery compartment for containing a battery, a battery compartment cap positioned over the opened-end with one side of the cap farthest from the gas cartridge being pivotably connected to the body and with another side of the cap adjacent to the gas cartridge including a releasible latch for releasable connection to the body, the latch including a slot allowing the latch to be opened with a tool when the gas cartridge is removed from the body.
Another object of this invention is to provide an autoinflator water-sensing circuit for sensing water between a first and a second water-sensing electrode protruding from a surface of the body and separated by protuberance means to hinder the bridging or pooling of water therebetween and causing unintentional actuation of the actuator assembly.
Another object of this invention is to provide an autoinflator water-sensing circuit including an activation timer for timing the duration of water immersion regardless of water conductivity, an activation timer reset for the activation timer to assure uniform water immersion regardless of previous water immersion history, and an activation duration timer for timing the duration of electrical current supplied to the fusing means.
The foregoing has outlined some of the more pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.